[XERCESJ-1276] Improve performance of XML Schema Identity-constraint validation --- XMLSchemaValidator$ValueStoreBase.contains() is painfully slow.

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.6.2, 2.9.1
• Component/s: XML Schema 1.0 Structures
• Labels: gsoc gsoc2013 mentor
• Assignee: Unassigned
• Reporter: Kenny MacLeod
• Created: 17/Oct/07 14:18
• Updated: 30/Aug/18 10:04

Description

Under certain conditions, the contains() method in XMLSchemaValidator$ValueStoreBase can cripple the performance of parsing and validation.

I'm not sure what those conditions are, but as a guideline figure I was using JAXB2 to deserialize a 22meg XML file. Without schema validation, it took 5 seconds. With validation, it took over 3 minutes (JDK 1.5.0_10 on win32). My profiler pointed the finger squarely at that method XMLSchemaValidator.

Suspicions were aroused further when seeing this comment in the source:

public boolean contains() {
// REVISIT: we can improve performance by using hash codes, instead of
// traversing global vector that could be quite large.

This is present in Xerces 2.6.2 contained with JDK1.5.0_10, and also in the source for 2.9.1.